921
FXUS65 KBYZ 221905
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
105 PM MDT FRI MAY 22 2026
KEY MESSAGES
- WARMING TREND AND MOSTLY DRY THROUGH MEMORIAL DAY; EXPECT
MOUNTAIN SNOW MELT TO INCREASE RIVER FLOWS.
- INCREASING POTENTIAL FOR SHOWERS AND THUNDERSTORMS BY MIDDLE OF
NEXT WEEK; DETAILS UNCERTAIN AT THIS TIME.
DISCUSSION
NEXT 7 DAYS (THROUGH NEXT THURSDAY)...
UPPER TROUGH WHICH AFFECTED OUR REGION THE LAST FEW DAYS IS
SLIDING EAST INTO THE DAKOTAS. WE STILL HAVE NW FLOW OVER OUR
REGION WITH A WEAK PERTURBATION UPSTREAM. THIS MAY KICK OFF SOME
ISOLATED SHOWERS LATE TODAY INTO THE EARLY EVENING...MAINLY FROM
YELLOWSTONE CTY NORTH AND WESTWARD AS WELL AS OVER THE MOUNTAINS.
HIGH PRESSURE BUILDS OVER THE SOUTHERN ROCKIES WITH ASSOCIATED
HEIGHT RISES ACROSS OUR REGION WHILE MAIN FLOW PATTERN REMAINS
ZONAL FOR THE WEEKEND. HIGHS WILL BE IN THE 70S SATURDAY AND 80S
BY SUNDAY WITH MOSTLY DRY CONDITIONS. TEMPS MAY PUSH 90 FOR MANY
LOCATIONS BY MONDAY AS FLOW ALOFT BACKS TO THE SOUTHWEST EARLY
NEXT WEEK AHEAD OF THE NEXT TROUGH MOVING INTO THE PACIFIC NW.
ENSEMBLES HAVE COME INTO BETTER AGREEMENT WITH REGARD TO THIS
PACIFIC TROUGH AS THE GFS MEMBERS HAVE TRENDED CLOSER TO THE ECWMF
SOLUTION OF DROPPING THE TROUGH INTO THE NEVADA AREA BY MIDWEEK
AS A CUT OFF UPPER LOW WHICH SITS THERE THROUGH THE FORECAST
PERIOD. THIS PATTERN FAVORS ADVECTING GULF MOISTURE NORTHWARD INTO
THE HIGH PLAINS AND IMPLIES AN INCREASING CHANCE OF
SHOWERS/THUNDERSTORMS FOR US TOWARD TUESDAY/WEDNESDAY. CLUSTER
ANALYSIS SUPPORTS THIS WITH 65% OF ENSEMBLES PRODUCING QPF ABOVE
THE OVERALL MEAN. PROGGED SFC CAPE VALUES OVER OUR EAST JUMP TO
600-1000 J/KG BY TUESDAY/WEDNESDAY WITH PWATS OVER AN INCH. THIS
COULD PROVE TO BE FIRST REAL THREAT OF STRONG/SEVERE THUNDERSTORMS
AND HEAVY RAINERS IN OUR CWA THIS SPRING. SO STAY INFORMED IF YOU
HAVE PLANS NEXT WEEK. LOOK FOR HIGHS TO BE PUSHING LOW 90S
TUESDAY BEFORE WE COOL OFF TO THE UPPER 70S AND 80S
WEDNESDAY/THURSDAY.
LAST NOTE...THE WARMER TEMPS WILL LEAD TO ENHANCED MOUNTAIN SNOW
MELT, WHICH WILL IN TURN RESULT IN INCREASING FLOWS ON AREA
RIVERS AND STREAMS. HEADS UP TO THOSE THAT WILL BE OUT AND ABOUT
OVER THE MEMORIAL DAY WEEKEND. BT
AVIATION
EXPECT OCCASIONAL MOUNTAIN OBSCURATION THIS AFTERNOON AND EVENING
DUE TO SCATTERED SNOW SHOWERS OVER THE ABSAROKA/BEARTOOTH AND
CRAZY MOUNTAINS. ISOLATED RAIN SHOWERS (10-20% CHANCE) ARE
POSSIBLE OVER THE PLAINS, DIMINISHING QUICKLY AFTER 00Z. ARCHER
PRELIMINARY POINT TEMP/POPS
SAT SUN MON TUE WED THU FRI
-----------------------------------------------------------
BIL 043/077 048/086 055/090 057/090 057/080 055/082 055/083
20/U 00/U 00/U 11/B 54/T 43/T 34/T
LVM 039/074 044/082 049/086 050/079 046/073 046/076 047/076
20/U 00/U 02/T 15/T 57/T 54/T 45/T
HDN 039/077 044/086 050/091 054/092 056/081 053/083 054/084
00/U 00/U 00/U 01/B 33/T 33/T 33/T
MLS 040/076 046/086 051/091 061/093 062/085 057/083 056/084
00/U 00/U 00/U 00/N 23/T 33/T 32/W
4BQ 039/074 045/085 051/090 060/091 061/083 056/080 055/083
00/U 00/U 00/U 00/N 24/T 44/T 32/W
BHK 036/073 042/085 049/090 058/090 061/084 055/081 054/081
01/U 00/U 00/U 00/N 13/T 33/T 32/T
SHR 034/071 039/081 044/086 048/088 048/079 047/080 047/081
00/U 01/U 01/U 01/N 25/T 34/T 34/T
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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